Objective. Because most Japanese soybeans are cultivated in paddy fields under rotational cropping, life cycle assessment (LCA) of soybean production needs to take into account a whole crop rotation including rice cultivation. In order to investigate the environmental impact associated with organic soybean production in Japan, this study carried out comparative LCA of organic and conventional soybean-rice rotation systems including 3-year organic and conventional rotations and a 2-year organic rotation. The inventories of arable products were built in the SimaPro software with the NARO LCI database, and were analyzed using the impact categories of global warming, acidification, eutrophication, non-renewable energy consumption, and pesticide application.
Results and Discussion. Organic soybean production reduced the environmental impact per 1 kg of soybeans in all the categories by more than 30% compared to conventional soybean production. The main contributors to the superiority of organic soybean production were decreases in direct field emissions and fertilizer consumption as well as the higher yield of organic soybeans. Sensitivity analysis demonstrated that organic soybean production remained more environmentally friendly than conventional soybean production, even if the yield of organic soybeans was assumed to decrease to 80% of the yield of conventional soybeans. However, the impact of organic rice production was significantly higher than that of conventional rice production in the categories of acidification and eutrophication due to overfertilization including rice bran and irregular soybeans for weed control. The impact of whole crop rotations was dominated in most cases by rice production owing to the higher yield of rice and the higher frequency of rice production. Consequently, the reduced impact of organic soybean production was canceled by the relatively large impact of organic rice production, depending on the impact categories; the impact of the organic rotation on acidification and eutrophication was higher than that of the conventional rotation. The 2-year organic rotation environmentally outperformed the 3-year organic rotation mainly because the effect of environmentally friendly soybean production had more influence on the former than on the latter.
Conclusions. This study showed that the environmental impact of organic soybean production was definitely lower than that of conventional soybean production. However, comparative LCA of whole crop rotations showed unfavorable results particularly with regard to acidification and eutrophication. This paper suggests two solutions to reduce the total impact associated with the organic paddy rotation including organic soybean production; one is reduction of organic fertilization in organic rice production and the other is introduction of a 2-year soybean-rice rotation.

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Objective. In recent years, hydrogen fuel is extremely expected as one of solution for global warming protection. Especially, in the near future, the bio-hydrogen fuel (Bio-H₂) due to biomass feedstock which is carbon-neutral would be promising as an eco-friendly fuel. Also, the Bio-H₂ production system through the biomass gasification process of Blue Tower process was developed as the commercial plant (15 t-dry/d) in Fukuoka, Japan. That is, it might be close for the eco-friendly fuel to be marketed. On the other hand, the market of smartphone grew and the annual sales recorded around 0.3 billion units. Thus, as one candidate of the device for which Bio-H₂ would be available, we focused on the smartphone with a PEFC (Polymer Electrolyte Fuel Cell) unit as an alternative to a Li-ion battery, and estimated the primary energy consumption and/or the direct and indirect CO₂ emissions using LCA methodology. In this paper, we investigated the influences of duration time and/or electricity consumption for each functional operation including the effect of exchange from a conventional cell phone to a smartphone. For instance, using the questionnaire on the usability of smartphone, we investigated the user condition in each generation which covered under 20’s to over 50’s. In comparison to the previous study, we clearly confirmed that the duration time was expanded. Also, we measured the operating electricity consumption of smartphone by the power meter, and investigated the PEFC performance through the basic experiments. Using the above research results, our purpose is to analyze the CO₂ abatement benefit of the smartphone with a PEFC unit fueled by Bio-H₂ against the conventional one with a Li-ion battery.
Results and Discussion. We evaluated the electricity consumption of talking, music, SMS (Short Mail Service), e-mail and internet access, which we intended in our study, and estimated the Bio-H₂ consumption for every operating period (OP) and for users categorized by each generation. For instance, the electricity consumption of under 20’s which is the largest value is 2.63 kWh/OP of OP=2.6 years and 3.74 kWh/OP of OP=3.7 years, respectively. Based on these results, on the Bio-H₂ consumptions in the cases of OP=2.7 years and OP=3.6 years, we estimated 0.98 to 1.49 Nm³/OP and 1.39 to 2.12 Nm³/OP, respectively.On the other hand, assuming the specific CO₂ emission of Bio-H₂ was 34.7 to 90.4 g-CO₂/MJ, the CO₂ abatement on direct emission would be approximately 60.4% to 86.8% in comparison to the conventional smartphone. In addition, we have a potential to obtain CO₂ reduction benefit in the total CO₂ emissions including the indirect one, even if the operating period is shorter. This would be due to the expansion of operating time for internet access and the higher efficiency of PEFC performance.
Conclusions. Due to the increase in energy consumption due to more convenient operations of a smartphone such as internet access and a higher performance of PEFC unit, the CO₂ reduction benefit against a conventional phone would be significantly obtained by the PEFC smartphone fueled by Bio-H₂.

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Objective. The objective of this study is to clarify the effect of consumers’ final demand in a metropolitan region on other regions by performing an interregional waste input–output analysis. We investigated the effect of consumption activities in Tokyo as a case study. We constructed the interregional waste input–output table for Tokyo for the year 2000 by using four main tables and data: the input–output table for Tokyo, the waste input–output table, the environmental input–output table, and inter-prefectural waste shipments data. Using the constructed table, we estimated the effect of consumption activities in Tokyo on the production value, value added, waste emissions, CO₂ emissions, and landfill consumption in other regions.
Results and Discussion. The estimation results showed that the effects of consumers’ final demand in Tokyo on other regions were not considerable, which is about 2 % of the total induced effect in other regions both environmentally and economically. However, these effects were not negligible either. The consumers’ final demand for Tokyo induced CO₂ emission which is 13.1 million ton-CO₂ in other regions, and this value is almost the same as that in Tokyo. The increase in the landfill consumption in other regions was about 1.2 million m³, which is about 2.5 times greater than that in Tokyo, owing to the effect of consumers’ final demand in Tokyo on other regions. On the other hand, the production value and value added in other regions owing to the consumers’ final demand in Tokyo was found to be 15.3 trillion and 7.0 trillion yen, respectively; the production value is half of that of Tokyo and the value added is a third of that of Tokyo.
Conclusions. Although the consumption activities in Tokyo produced economic benefits in other regions as well, the increase in the environmental loads owing to such activities was considerably greater than the increase in the economic benefits. Hence, it is important to discuss not only obvious environmental loads but also the hidden environmental loads owing to the consumption activities in metropolitan regions.

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Background and Objective. As Japan’s population has aged, the amount of disposable diapers discarded has steadily increased. At present, disposable diapers from households are incinerated as general waste and disposable diapers from care facilities and hospitals are incinerated as business or industrial waste. Current recycling methods for disposable diapers include thermal recycling and material recycling. However there are many problems with recycling process such as sanitary issues of diapers caused by the attached waste and problems on separating them. As a result, recycling of disposable diapers is primarily conducted at waste-power generation plants and not at other garbage processing plants. Technology to extract recycled pulp from used disposable diapers is currently being developed with the goal of creating a recycling system that would allow disposable diapers to be produced from recycled disposable diapers. In this study, we carried out a life cycle assessment (LCA) for a water-based recycling system and existing incineration disposal methods for disposable diapers.
Evaluation Objective and Analysis Method. The reduction of environmental load was evaluated by calculating carbon dioxide emissions with an LCA method. The evaluation begun after disposable diapers being transported to the recycling plant, and ended when they were broken down into different materials and were ready for secondary reuse. The comparison target is incineration and landfill disposal on the assumption that this is the traditional treatment for used disposable diapers. The functional unit is the annual amount of used disposable diapers delivered to the recycling plant.
Conclusions. Carbon dioxide emissions were lower in the water-based recycling system as compared with disposal by incineration. For this type of recycling business to be sustainable, however, payability is the most significant problem. From a standpoint of continuity and development of recycling, it will be very important to construct a stable collection system of used disposable diapers. A subject for future study is to quantitatively show the effect of expanding the recycling area.

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Background Aim and Scope. Hokkaido University is one of the largest general business institutions in Hokkaido Prefecture, and is now socially required to reduce its greenhouse gas (GHG) emission such as CO₂ and N₂O on campus. The campus can be regarded as a miniature town, and several trial experiments and measures have been applied to the campus to reduce environmental burdens including GHG emission. Such activities are called “Sustainable campus activities”, and have been implemented in many universities all over the world recently. Hokkaido University is now trying to establish a recycling system of organic wastes on campus. This study aims to examine the possibility of introducing the recycling system, by assessing the effects in terms of GHG reduction and economic effects.
Material and Methods. To figure out the current status of organic wastes on campus, we came in for an interview to officers in Hokkaido University and the CO-OP. The current organic waste management on campus was clarified by the interview. For a comparative study to the current system of organic waste treatment, two new recycling systems of organic wastes were assumed in this study. One of the new systems is that in which all the leftover food from the university cafeterias and hospitals is assumed to be composted and all the dead and pruned branches are assumed to be chopped and sheeted on trails on campus (Scenario 1). In the other new scenario (Scenario 2), all the dead and pruned branches are assumed to be chopped and be utilized for fuel of wooden chip stoves as alternatives of part of the oil stoves on campus, while the leftover food is assumed to be treated in the same way as in Scenario 1. The Life Cycle Assessment was applied to the current system and the two new scenarios to examine the most adequate recycling system of organic wastes on campus, by comparing the GHG reduction as the representative of the environmental effects. Similar assessment was also performed to examine the economic effects of introducing the new recycling systems.
Results and Discussion. The effect of GHG reduction on campus by Scenario 1 and 2 was estimated to be 63 t-CO₂/year and 161 t-CO₂/year, respectively, compared to the current recycling system. This means that both of the scenarios can contribute to reduce GHG reduction on campus, and the effect is especially prominent in Scenario 2 by replacing partly oil stoves with wood chip stoves. The initial cost, running cost, and income by establishing Scenario 1 was estimated to be 37,210,900 yen, 934,000 yen/year, and 2,150,000 yen/year, respectively. Similarly, the costs and income for Scenario 2 was estimated to be 61,210,900 yen, 934,000 yen/year, and 4,911,200 yen/year, respectively. This means that the initial and running costs can be paid off in 31 years and 15 years for Scenario 1 and 2, respectively.
Conclusions. While this study demonstrates that the two new recycling systems of organic wastes are both effective in GHG reduction on campus, the economic effect of introducing the new systems is still controversial. If we assume that the general durable years of the facilities introduced in the new systems are 20 years or around, Scenario 2 is considered to be worth being introduced with regard to both environmental and economic effects. Moreover, Scenario 2 will be economically more effective in future because oil prices are supposed to keep rising. The new recycling systems can also lead to more job opportunities on campus. Such results are considered to be of some help for local municipalities in Hokkaido Prefecture in a cold district and with a large amount of biomass to design future policy making for balancing environmental conservation and regional vitalization.

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Objective. For creating a sustainable society, it is important to change citizen’s life style and sense of values. Environmental education is expected as a way of solving those problems. The authors have developed an environmental education program using educational LCA software “global warming even in your bag?!,” which aims to make learners realize the link between our daily life and global warming based on life-cycle thinking, and has implemented the program in several junior high and high schools. While the effectiveness of the program was demonstrated through the implementation, some problems to be solved for the wide use of the program in the future came to light. The present study aims to identify points to be improved in the program to newly develop more effective software for the program.
Results and Discussion. Analysis on students’ impression and teacher’s comments obtained from the program implementation in the past reveals that it is necessary (1) to more emphasize the link between our daily life and global warming, (2) to reduce the burden of teachers, and (3) to improve life cycle CO₂ emission calculation. In order to solve the three problems, new software “global warming even in your bag?! Ver. 2” is designed and developed. First, “life cycle flow screens” are introduced so that learners can study various product life-cycles only using the software. Second, graphical user interfaces (GUIs) are improved in view of user-friendliness for both teachers and learners. Third, life cycle CO₂ emissions are calculated more appropriately reflecting the characteristics of products.
Conclusions. An environmental education program using “global warming even in your bag?! Ver.2” is expected to be more effective for realizing the link between our daily life and global warming based on life-cycle thinking, and for reducing the burden of teachers. Actually, a teacher who implemented the programs using Ver. 1 and Ver. 2 offered the comment that the use of Ver. 2 allowed for giving a lecture more smoothly compared to Ver. 1.

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Objective. In this study, we performed a comparative life cycle assessment（LCA）of two production systems for spinach for processing use: mechanized production system and conventional production system. We estimated greenhouse gas emissions in both systems, compared them in terms of superiority or inferiority, and considered the impact on global warming of the mechanization of spinach for processing use production.

Results and Discussion. The emissions of greenhouse gases in the mechanized production system amounted to 318.5kg per 1000 square meters, and those of the conventional production system were 311.8kg. This indicates that the greenhouse gases emissions in the mechanized production system surpassed those in the conventional production system by 2%. The fertilizer manufacturing process was the largest emission source in both systems. The emissions per unit area from the mechanized production system were reduced along with enhancement of the operation rate.

Conclusions. The greenhouse gases emissions of spinach for processing use in the mechanized production system surpassed those in the conventional production system by 2%.

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Recently mobile phones have become more multifunctional and can be used as digital cameras, game consoles and music players. In other words, mobile phones can make it possible to reduce the consumption of the natural resources used to fabricate these small electronic devices. The objective of this study is to analyze the metal components of mobile phones and compare with those in other portable electronic devices. The metals contained in these small devices were chemically analyzed using ICP-MS, ICP emission analysis and gravimetric analysis. Then the environmental impact was estimated in terms of the CO₂ emissions in the production of the metals. The results showed that the metal resources in a mobile phone weighed about 35% of that in the other devices and simple phone, thus indicating that mobile phones can reduce resource consumption by about 65%. Moreover, there was some reduction in the CO₂ emissions.

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Recognizing electric energy consumption in households could lead us taking actions for energy reduction. Thus the purpose of the research was set to clarify the amount of electric energy consumption related to food consumed in households. The first phase of the study was to measure the amount of electric energy used while cooking with the use of rice cooker, microwave and electric pot. They are considered to be the main source of electricity while cooking. The annual electricity consumption of electric rice cooker was estimated as 63.0 kWh per household per year. It was calculated from 214 times of use for cooking per year and 6 hours for keeping warm. Although the ownership of electric rice cooker in Japan is as high as 90% (according to Japan Electrical Manufacturers’ Association), it was estimated to contribute only 1.2% of domestic household electricity consumption in 2008 based on the result of the measurement. The electricity consumption by microwave was 58.6 kWh per household per year (the constituent ratio was 1.1%). The annual electricity consumption of the electric pot usage (for boiling water and keeping warm) was 154 kWh per household per year and its constituent ratio was 2.8%. The electricity consumption for keeping water warm for 24 hours after boiling was 0.733 kWh which was 2.6 times of that of boiling water (0.286 kWh). The electricity consumption of the three major household electric cooking devises; electric rice cooker, microwave and electric pot were estimated as 276 kWh per household per year, which was 14.4 TWh per year and accounted for 5.0% of Japanese household electricity consumption. When considering of reducing CO₂ emission related to household food consumption, it is necessary to search measures to reduce energy consumption without losing the characteristics of food itself as food is the source of our health. How to reduce energy consumption of household cooking will be discussed in the future when the actual usage of other household devices such as refrigerator and dishwasher, and the electricity consumption of those devices are estimated.

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In this study, we analyzed the CO₂ emission of commuting to Taihaku Campus, Miyagi University. For each commute to the school, the CO₂ emission per student was found to be larger than that per university staff. The current activities have not been effective on the abatement of CO₂ emissions at campus. Therefore, we evaluated an effective methodology, namely, the construction of an eco-campus, for reducing environmental loads and enhancing the students’ sense of responsibility toward the sustainable environment. Further, we believe that presenting the CO₂ emission data to the students might persuade them to limit the use of their own vehicles.

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